System of wiring conduits for building construction



March 17, 1925. 1,530200v H. F. RICHARDSON. ET AL SYSTEM OF WIRING CONDUITS FOR BUILDING CONSTRUCTION Filed Nov. 4, 1921 5 Sheets-Sheet l -F/'yl- F57 a March 17, 1925. 1,530,200

H. F. RICHARDSON ET AL 'SYSTEM 0F WIRING CONDUITS FOR BUILDING CONSTRUCTION Filed Nov. 4, 1921 5 sheets-'sheet 2 ,F F' 8 T WHA/5555 t Juventus j I @www c Y March 17, 1925. 1,530,200

H. F. R|CHARDSON ET AL SYSTEM OF WIRING CONDUITS FOR BUILDING CONSTRUCTION Fi1ed Nov, 4, 1921 5 Sheets-Sheet 3 March 17, 1925. 1,530,200

H. F. RICHARDSON ET AL SYSTEM OF WIRING CONDUITS FOR BUILDING CONSTRUCTION Filed Nov. 4, 1921 5 Sheets-Sheet 4 JZ-IC 5T March 17, 1925. 1,530,200

H. F. RICHARDSON ET AL SYSTEM 0F WIRING GONDUITS FOR BUILDING CONSTRUCTION FiledNov.v 4, 1921- 5 Sheets-Sheet 5 vPatented Mar. 17, 1925. l l

UNITED STATES PATENT oFFlcE.

HENRY F. RICHARDSON, O'F BROOKLYN, AND ALLAN COGGESHALL, 0F PLEASANT- i VILLE, YCRK.

SYSTEI F WIRING CONDUITS FOR BUILDING CONSTRUCTION.

Application tiled November 4, 1921.

.To all whom t may concern:

Be it known that we, HENRY F. RICHARD-v soN and ALLAN CoGGEsHALL, citizens of the United States, and residents, respectively, of Brooklyn, county of Kings, city and State of New York, and Pleasantville, county of Westchester, State of New York, have invented certain4 new and useful Improvements in Systems of W'iring Conduits for Building Construction, of which the following is a specification.

Our invention relates in general to systems of electric wiring and more particularly to a wiring conduit or duct system 145v for use in building construction.

Present day methods of building construction, as embodied for example in the case of vfactories and large olice buildings, have reached a highl l.specialized condition;

Steel and reinforce" concrete, are practically'rquired toredu'ce lire risk and to obtain strength anddurability with economy. The use oficcncrete for` forming the floor slab has made the problem of electric wiring a diiiicult one, on account of the inherent d-iculty of subsequent alteration or exten sion ofthe usual type of wiring laid within the concrete. 0n this account, the-practice has been to ligure in advance the probable need and location of outlets for annunciator, telephone, lighting and other lines, so as to reduce tov a minimum the subsequent alterations necessary. y

The principle underlying our present lnvention is just lthe reverse of the present day ractice, and aims to give the maximum gacility of accommodation to subsequent demands, and to avoid lthe necessity of arrangin outlets in advance at predetermined points that may or may not be subsequentlyused, The .principle is eually 'a plica'ble in many ofits features to oor, wa 1 or ceilv ing construction, but will be herein described withreferenceto floor construction in particular.

The general principle involved in our invention is based on the idea ofso arrangf ing the wiring ducts or conduits beneath the surface of the floor` or the like that access tothem, after the ,-floor has been completed, can be readily 'gained by cutting through the floor and into the ducts and installing an 'outlet fitting; where the need has oc- Serial No. 512,825.

curred. In carrying out this principle, the conduits are themselves, so disposed as to be available for being placed in service substantially Wherever the subsequent need may arlse. That is to say, a long, narrow space, within t-he length of which there may subsequently be required one or more outlet connections as for machines, desks or other articles or furniture, might be adequatelyy provided for b a single, continuous conduit or duct. n the case of floor space of greater width so that there may be somel uncertainty as to both longitudinal andlateral disposition of the articles or furniture to which connections may have to be brought, the system may comprise a plurality of continuous conduits or ducts, either ter where the desk or the" like may 'subsequently be placed on the floor, a duct or conduit, or some branch thereof, will be the desk or substantially so. The invention further comprises a novel arrangement for distributing such a system of ducts or vconduits beneath the surface of the floor to lcarry conductors of two different kinds, which require separate passages as for eX- ample electric light wires and -annunciator wires. Two such systems may, according to our invention, be distributed vthroughout the .floor space withoutthe necessity of the conduits of one system paing over or under those of the other, all of which will be more fully explained hereinafter.

In reducing the principles of our invention to practical commercial form, it is, of

"course, evident that economy and eiliciency must be considered.- For example, according to our invention, the Hoor or the like branched or unbranched, so arranged be .neath the surface of the licor that, no matvfound to be available immediately beneath surface of the Hoor and to apply the outlet fixture when the occasion demands. In systems, which have already been installed under our invention, wehave found the use of a duct constructed of wood or paper fibre composition to satisfy the above requirements of economy and facility of operations. A third feature of importance is the economy of space, especially in vertical direction, and to avoid or minimize the weakening ofthe concrete ioor structure itself by the provision of the ducts or conduits beneath kits surface. We have adopted, in practice, for this reason, a fibre conduit of substantially half-round section with its curved surface uppermost, thus offering relatively great capacity for wires while avoiding excessive height. At the same time, this low, but relatively wide, shape of the conduit is much easier to strike in cutting through the concrete above it and gives a greater area laterally or transversely within which the outlet fixture may be applied. In addition to these general features of the invention, we also provide improved forms of fixtures to be employed in conjunction therewith, examples of which will be hereinafter referred to.

To clearly illustrate the principles of the invention, we have shown, by way of example in the accompanying drawings, certain embodiments thereof, which will now be described.o

Referringto said drawings Figures 1 and 2 represent in diagram matic plan View and transverse vertical section a floor construction, in which a single duct or conduit is installed under the principles of our invention.

Figures 3 and 4 are similar views representin the same construction after an outlet fitting has been applied.

Figures 5 and 6 are longitudinal vertical sections of the same form of the invention, Figure 5 indicating the conduit in place within the completed floor prior to the application of an outlet fitting thereto, and Figure 6 representing the same floor and conduit with one outlet already applied and operations for the introduction of a second outlet begun.

Figures 7, 8 and 9 are detail transverse sections of three different forms of conduit which may be employed in the system.

Figures 10 and 1l are vertical, transverse sections through two forms of outlet fittings applied to the conduit.

`Figure 12 is a transverse section through a floor containing a half-round conduit, showing' one way of cutting through the floor to reach the conduit.

Figure 13 is a similar view with a special form of outlet fixture introduced.

Figure 14 is a top plan view of the outlet fixture shown in Figure 13.

Figure 15 is a diagrammatic plan view of a system embodying se arate branched conduits for two diilerent inds of wiring.

Figure 16 is a top plan view with parts in horizontal section showing a particular fflirm of junction box, which we may em- Figure 17 is a vertical section therethrough with parts shown in elevation.

Finure 18 is a detail vertical section, taken lon ltudinally, of a special form of crossun cr fitting, which may be employed in the system under certain conditions.

Referring to Figures 1 to 6 inclusive, 25 indicates an I-beam, 26 Athe main body of concrete, known in the trade as the arch or slab' and 27a loose lill of, for example, cinder, within which is embedded the duct or conduit 28. 29 may indicate the thin surface layer of concrete or cement and 30 the linolcum or other floor covering laid thereon. It will be understood that the particular structural or load-supporting elements of the floor construction are not, in themselves, special features of our present invention, and the design illustrated in Figures 1 to 6 is merely intended to be 'diagrammatic of any approved type. The term floor slab as used herein includes the floor and ceiling constructions common in the steel and reinforced concrete art referred to in the statement of invention, seine specific forms of which are disclosed herein and when this element includes the wire duct forming a art of our invention is distinguished in 1ts various forms by the fact that there exists between said wire duct and a surface of the slab a layer of concrete-like material forming an essential portion of the slab and penetrable to form an outlet from the wire duct. Assuming the construction herein shown, the duct or conduit 28 is laid on y the more or less smooth surface of the concrete body 26 in the course of the construction or laying of the floor, and before the bed of cinder or the 'like 27 has been laid. lle have indicated, by heavy line 31, in Figures 2 and 4, a levelling or sealing layer, against which or on which the base of the conduit may be laid. This layer may, for example, be a coat of as halt paint, or a thin slab of cement, or ot 1er levelling material, to facilitate the laying of the conduit. After the conduit has been laced thereon, it may be prelimina-rily held down by applying cement, mortar or similar material along the outer edge of its base, as indicated at 32, which, at the same time, may constitute a seal for the base of the conduit where 'and the floor surface finished off with cement or concrete 29 and, if desired, covered with linoleum or other covering 30. The construction, as shown in Figures 1, 2 and 5, indicates one embodiment of the invention ready to be placed in service by being supplied with conductors and outlet fittings when needed. In Figure 3, we have indicated by dot and dash lines 35, the location of a desk or other piece of furniture to which it may be desired to bring -a connection from the floor. The outlet fit-ting is represented at 36 in this figure and also in Figures 4: and G, and is indica-tedin these figures as having been installed. By referring to Figure 6, the method of placing the conduit' in service will be clearly understood. Here the surface of the floor is indicated as having been chiselled or cut through y duct or conduit element.

at 37 to expose the top of conduit 28 and, inthis exposed condition, the perforation for the reception of an outlet fixture can be readily made through the to of the conduit as by chiselling, drilling or y means of an ordinary Wood auger., in the case of fibre conduits such as above referredto. After the outlet -fixture has been inserted, the

spa-cey around the same may be filled with grout or cement to sea-l the joint and otherwise com lete thework. Suitable forms of outlet fittings and more detailed description of the manner of finishing the installation of same will be given with reference-to figures of the drawings to be subsequently described.

We have alreadyv suggested the importance, on a commercialor economic standpoint, of a special form and construction` of In Figures 7 8 and 9, we have illustrated three shapes of conduit which we may assume to be constructed of paper or wood fibre composition. The round fibre conduit is already known and extensively used, but we have designed,

as a part of the present invention, a noncircular shape of conduit, of which three examples are given in Figures 7, 8 and 9. Figure 7 showsv a half-round conduit 39, open atthe bottom, which may, for example, be made by splitting longitudinally into two halves the well known circular fibrev duct or conduit. Figure 8 represents a D- shaped section of a lconduit 40, whichm-ay be molded in 4one piece or constructed of two parts cemented or otherwise joined together. Figure 9 represents a similar shape of conduit produced by fittingthe open bottom conduit 41, such as shown at 39, in Figure 7, with a flanged bottom portion 42, which may be of any desired material, for example, fibre, galvanized iron or the like. It will be noted inl the examples illustrated that relatively large interior capacity is gained per unit of height, and at the saine time, the width is such as to malte it easier to locate the conduit beneath the surface of the door and apply the fitting tothe top y thereof.

Two forms of outlet fixture are shown by way of example in Figures 10 and 11.- It will. be understood that the outlet fixtures are to be of sufficient size and dimensions to permit the fishing of the conductors through the same. Its junction with the conduit should be effectively sealed and, for this reason, we prefer in most instances to screw or thread the fitting into the duct. This latter operation can be readily accomplished by inserting the fixture into a perforation in a fibre conduit such .as we have described, without the necessity of first tapping or threading the hole which has been bored or cut through the conduit. The outlet. fixture is preferably so arranged as to be flush'at the top of the surface of the floor or floo-r covering and this result is readily obtained by screwing the fixture in or out, at least Within the range of its screw threading. T he physical character of the fibre conduit is such as to accommodate the slight straightening movement which may be necessary to bring the fixture into correct vertical alinement. The depth of the conduit beneath the floor surface may be relatively slight in some cases and greater in others and, for this reason, we provide outlet fixtures of varying degrees of adjustability as to height. Figure 10, for example, shows an outlet fitting provided with a tubular body portion 50, which is flared at 51 to avoid the necessity of a sharp bend in the wires, which are brought through the outlet. The body portion 50 is also enlarged or flanged at the bottom "in this example and is threaded at 52 so as to be screwed into `the opening formed in the top of the conduit 28. An adjustable extension 53 is threaded on to the upper portion of the body 50 and flanged at thetop 54 so as to give the effe-ct of a floor plate, which is to'be carefully adjusted to the level of the floor or floor covering The extension 53, having been adjusted to the proper elevation, may be locked in this position by means of the lock nut 55, which is threaded on to the body portion 50 prior to the application ofthe extension 53 thereto. An inner flange 56 is formed on theinterior of the extension 53 to constitute a seat for a seal or gasket 57 of compressible material vsuch as fibre, rubber, lead or the like.

This seal is pressed by a plug 58, which is 53, and may be screwed-in or out, for example, by means of a screw driver applied to the screw head slot 59, so that a neat and smooth top surface is provided for the outlet when not in use. When the outlet is placed in use, 'the flange 56 and gasket 57 serve as a shoulder or stop against which the extension element may abut and thus the joint be made watertight.

The form of outlet connection shown in Figure 11 is adjustable in the sense that it may be screwed further in or out with respect to the conduit 28; but this form of the outlet fitting lacks the special adjustment collar or sleeve illustrated in Figure 10. It is for use where, perhaps, less extent of adjustability is required. As illustrated, it comprises a body portion 60, flared at 61 and threaded at 62, by which thread'ng it may be screwed into the perforation formed in the fibre conduit 28. The upper portion of the fitting is formed with a rim flange 63 to be flush with the floor surface and in the interior of the fitting may be screwed a plug 64, which may seat against an elastic or yield'ng gasket 65 supported on an inte- -rior shoulder 66 of the outlet body 60. A screw slot 67, or other similar means, may

i be provided in the upper face of the plug 64 to ermit the plug tolbe turned by a screw river or other suitable tool.

A third example of an adjustable outlet fitting is illustrated in Figures 13 and 14. In this construction, the conduit 28, which has been perforated as before descrlbed, has

threaded into it the main body portion 68, which is flared at the bottom, as before described, and threaded at 69 to enable it to be screwed into the perforated conduit. This body portion 68 terminates below the floor level, when adjusted, and has in its upper portion an internal threading 70, to receive the external threading 71 of the adjustment neck 72, which latter is flanged,

as shown at 73, to be adjusted flush with the surface of the floor or floor covering and at the same time entirely fill the hole cut in the surface covering so as to present a continuity of floor surface without the necessity of intermediate patches of the floor covering. The neck 72 is screwed up or down within the outlet body 68 to properly adjust this level and to facilitate this operation, it may have recesses 74 in its upper face suitable for the reception of an operating tool. An inte-rior plug 75 may be screwed into the threaded neck 72 to close the aperture thereof, a screw head slot 76 or similar construction being provided for operation of the plug by means of a screw driver or the like.

Figures 12 and 13 will serve to make clear a' method of applying the outlet fitting to the duct lying beneath the surface of the finished floor. 8O may represent the concrete floor structure on which a layer or slab of plast-ic material 81 is laid for the reception of a half-round fibre conduit 82, which is surrounded by, for example, a loose fill of cinders 83', on which is la-id the upper layer of concrete or cement 84, covered by linoleum or the like 85. Havfng determined the point at which an outlet fitting is to be inserted into the conduit section 82, a sheet metal or otherwise formed guard 86, having a flanged aperture 87 corresponding in diameter with the necessary size of openin to be cut through the floor surface, is emp oyed to protect the floor surface and covering 85 during the work on the job. A circular disk of the floor covering may be removed to permit the reception of the flange of aperture 87 and thereafter the relatively thin layer of concrete or cement 84 is cut away or chiselled out and the hole extended down through the cinder fill 83 until the to of the conduit 82 lies exposed. An or inary wood auger of suit-- able size may now be employed to cut through the top of the fibre conduit 82. The s1z'e of the aperture formed in the -conduit will be so selected as to enable the threaded rtion of the outlet fitting to be forced into it by turning so that the result is a screw thread connection between the duct and the fitting withouthaving prev viously tapped the aperture by a special tool. AHaving inserted the body portion 68,

the space surrounding same will be filled up, to wfthin a short distance of the top, by grout or cement, as indicated at 88. The protecting form or guard 86, 87 may then be removed and the outlet neck 72 inserted, its flange 73 approximately fitting the opening made through the floor covering 85 so that a neat and tidy joint is formed. The plug 75 Amay be inserted when desired to close the aperture of the outlet. By the use of the method described, vinstallations of outlets can be made after the floor has been finished and without dsfiguring the floor covering, which is left in place upon the floor vsurface during the operations described.

The` description thus far has been devoted principally to the features directly bearing upon the installation of the outlet fittings. The invention further comprises certain iinproved constructions and arrangements for distributing and connecting the conduits or ducts in an especially advantageous manner. In Figure 15, for example, we have shown a composite system in which two entirely separate systems of duct or conduit are arranged to parallel each other throughout 1 lOl) llO

them at any point where a connection may be found necessary. This result may be accomplished without the necessity of running the duct of one system over or under that of another and thus we avoid the doubling of the vertical space occupied by the wiring ducts within the door. Certain junction boxes and other fittings in addition to the conduit sections themselves are employed in a practical carrying out of this featurel of our invention, but We shall first describey the same in diagramy and then explain more in detail a construction which we have found satisfactory for the junction boxes and other necessary appurtenances. Referring in detail to Figure 15, it will be Vobserved that the system`comprises two separate and distinct systems of conduit which we may represent as systems A and B respectively. We may assume, for the sake of illustration, that system A represents telephone wiring and system B the annunciator or electric light wiring. Our invention doesnot aim to prescribe What systems shall be kept separate, but rather provides the means of keeping them separate when such condition is required.

Each system comprises one or more conduits 10031003, which extend continuously or straight through from one side lof the space to the other, from which are laid the transverse or lateral communicating branches or extensions 101A, 101B. Inlaying the systems, the conduits of system A alternate with those of system B and are spaced apart at more or less uniform intervals, as illustrated in Figure 15. The conduits 100A, 100B may, for example, be approximately parallel to each other and simila'rly the extensions 101A, 101Bv may be parallel toeach other. Obviously, the formation of rectangular spaces is optional as the same principle may be advantageously applied so as to produce figures of other shapes where the shape of the space to be `covered is different. For example, they may be arranged in parallelograms where the shape of the room is that of a parallelogram. The connection of the branches with their straight-through conduits is effected by junction boxes, such as diagrammatically illustrated atr102 in Figure 15. It will be seen that these branches extend from one system toward the next, but terminate just short thereof, so that all the conduit sections may be substantially in one plane and the necessity of permitting one to "cross over, above or below another is avoided. In actual practice, the dimensions of the intervals between the two systems and the successive conduits of each system are so selected that no point on the oor space will be more than a certain minimum distance from a conduit or branch of either system. This particular distance Amay be figured on the basis of the size of furniture so that, for example, assuming a desk of ordinary size, some part of the desk, no matter where placed on the floor space, would be approximately over some part of each system of conduit. In this way, an out- 'let connection for extending the service to the desk could be made through the floor either underneath the desk or substantially at the edge of the desk, thus avoiding the encumbrance, of what should be free walking space, with wires. IVe have indicated diagrammatically at 103 the location of outlet fixtures, which may, for example, be originally installed under the principles already described and closed by their floor plates or plugs so as to be available without the necessity of cutting through the floor. These however, might be omitted, and they are only shown. in this figure to indicate that outlets may be placed in advance of demand if so desired. The system is still readily available for the installation of additional outlets to meet subsequent requirements. Ordinarily, the conduits are not originally Wired but are so constructed that Wiring can be readily introduced into them when necessary. We have shown, for example, the supply of wiring to system A by ducts 104 leading from the wall and tosystem B from wall boxes 105 leading into vthe end of the conduit itself. These illustrations are merely by Way of example. It will be understood that such connections afford communication or distribution of the service from floor to floor, or from room to room on the same floor. The construction and arrangement of the individual lines of conduit may follow, for example, the general construction shown in and described with reference to Figures 1 to 6 of the drawings.

There may be for certain reasons a desirability of departing from the described purpose of arranging all the conduits substantially in the same plane or on the same level. For example, it may be required that certain space beneath the floor surface be left, within which to place piping or other duct system, which must be crossed by a Wiring duct such as We have set forth. Figure 18 illustrates an example of a special fitting, which may be employed for this purpose. In this figure, it Will be seen that the duct sections and 111 are joined together b a crossunder connection duct 112, which leaves the space above it for piping or duct 113 running transversely thereof. This principle is, of course, only applicable where permitted by the height or construction of the floor proper.

The junction boxes vshown diagrammatically at 102 in Figure 15 are intended to be flush with the floor'surface and serve to join together the duct sections. They are adapted to be opened at the top when itis desired to gain access to the junction for the purpose of drawing wires into the adjoining parts of the duct system or for performing some other operation thereon. 1t should be borne in mind that, ordinarily, the ducts are not supplied with wiring When first laid, but those portions `of the ductV system which are placed in commission will be wired when the need arises. We have shown in Figures 16 and 17 an embodiment of a satisfactory form of junction box.

Referring to Figures 16 and 17, the junction box here illustrated comprises a body of, for example, cast iron made up of a fioor or bottom 114, and side walls 115 which are open on all four sides to receive the duct sections 116 and provided with corresponding flanged sockets 117, into which the ends of the duct sections fit more or less closely. The corners of the body portion of the junction box are, in the present example, arranged at say forty-five degrees to the side walls to form diagonally opposite faces 118, which-are perforated and tapped at 119 to receive a threaded iron pipe or conduit when it is desired to lead a forty-live degree connection into or from the junction box. The upper portion of the bod is formed with an internal, horizontal le ge or flange 120 which surrounds the central opening of the junction box, through which access is gained to .the interior.` An upwardly extending rim flange 121 serves to prevent 'the fill of cinder 122 and surface cement 123 from etting into the interior of the junction ox during the process of laying the floor structure around the junction box, and also provides an interior pocket or chamber to receive the junction box cover and its associated arts, which will be ex lained. The rim ange 121 terminates a sight distance below the level of the floor surface. The cover and floor plate are to be adjusted to lie flush with the floor surface. For this purpose, vwe provide a rim plate 124, which as an inner flange 125, through which pass a suitable number of screws 126 that are threaded into the inner flange 120 of the body portion of the junction box, to secure the rim plate 124 to the said body. The screws 126 are turned in or out to raise or lower the level of the rim plate 124 so that its upper edge is :just fiush with the fioor surface or iioor covering and the lock nuts 127 are then tightened vupwardly aca-inst the under face of the flange 125 to definitely fix the plate at that elevation. If desired, a collar or gasket 128 of suitable thickness may be disposed beneath the lower edge of the flan e plate 124. The floor plate 129 is herein ilustrated as countersunk to receive a sheet of linoleum 130 to match the floor covering. This floor plate may be of brass and preferably has stren hening ribs 131 formed inte al therewit and extending along its un er surface. It fits within the interior of rim plate 124 and may be secured therein by means of countersunk screws 132, which are threaded into the flan e 125 of the rim plate, as shown clearly in l* igure 17. A gasket 133 of yieldinfr material ma be confined 'between the ower edge of tlie floor plate 129 and the upper surface of the fiange 125 to make the joint water-tight.

lVe have shown in Figures 16 and 17 a construction by which the grounding of metal armoured cable may be accomplished in the junction boxes, as required b insurance regulation. The two armoure cables are indicated at 134. Their ends are drawn part way into the junction box and clamped beneath a metal oke 135 by, for example, a screw 136 threa ed into the bottom of the cast iron body portion of the junction box.

It is thought that the description above given will be suiiicient to enable those skilled 1n this art to understand and practice the invention. It has already been explained that the principle involved is to distribute the conduit within the bod of the floor structure atthe time of building the ioor and to lay the conduit preferably at refrular ooy intervals based u on assumed standards of l size of oflice furniture or the like to which the service may have to be supplied.A That is to say, it is the intent, primarily, to provide conduits at such intervals apart within the floor area that connection through floor fixtures may be gained substantially beneath the desk, machine or the like, no matter where the latter is placed upon the fioor. The. wiring is only introduced where wires are found to be necessary. When the wiring is required, it is readily introduced into the system by the well known practice of so-called fishing, the junction boxes and outlet fixtures giving access to the conduit for this purpose. The junction boxes are ordinarily installed throughout the system in the beginning, whereas the outlet fixtures are readily introduced where desired when their need becomes apparent. The sup ly of wiring to the conduits from the wal boxes or shafts may be accomplished by drawing the wires through the adjacent ends of the conduit or through` special iron pipe conduits led into the junction boxes on the forty-live degree faces thereof, as alpermit the fishing of wires through it and, at the same time, the Width of the conduit into which the outlet fixture is to be threaded should be such as to provide ample extent of space horizontally to permit the introduction of the outlet fixture inthe manner decontour and Without leaving ragged burs or edges.

The junction boxes as already described, are constructed of metal, whereas in most cases, the conduit itself will be of non-metallic fibrous material, such as Wood, fibre or paper composition. All metallicparts of a conduit system for high tension Wiring, such as electric lighting circuits, are commonly grounded, and we conform with the practice by grounding the junction boxes in any approved manner.

lVe claim 1. The steps in a method of building, which comprise constructing a floor slab including a wire duct within and substantially parallel with the fioor surface of the slab, cutting through the slab into the duct at a point determined by the location of a device to be supplied With current whereby conductors may be led through said duct to said device.

2. The steps in a method of building, which comprise constructing a flo-or slab including a Wire duct within and substantially parallel with the floor surface of the slab, cutting through the slab into the duct at a point determined by the location of a device to be supplied with current and applying a fitting to the duct through which the conductors may be rawn. i

3. The steps in a method of building, which comprise constructing a floor slab including a wire duct within and substantially parallel with the fioor surface of the slab, cutting through the slab into the duct at a point determined by the location of a device to be supplied withcurrent, applying a fitting to the duct, and filling the space around the fitting with cementitious material.

4c. The steps in a method of building, which comprise supporting a system of conduits substantially parallel with the floor surface, constructing a floor slab to include the conduits, and cutting through the slab into the conduit at a point determined by the location of a device to be supplied with current, whereby conductors may be led to said device.

5. The steps in amethod of building, which comprise supporting a system of conduits substantially parallel with the floor surface,

constructing a floor slab to include the conduits, cutting thro-ugh the slab into the conduit at a point determined by the locati-on ef a device to be supplied with current, and applying a fitting vto the conduit, whereby conductors may be led to said device. l t

6. The steps in a .method of building, which comprise supporting a system of co-nduits substantially parallel with the fioor surface, constructing a floor slab to include the conduits, cutting through the slab into the conduit at a point determined by the location of a device to be' supplied with current, applying a fitting tothe conduit,l

and filling the space around the fitting with cementitious material.

7..In combination, a fioor slab, a duct within lthe slab, a fitting having a part narrower than the duct adapted to be fitted into the upper part of the duct and extend through the Hoor to the surface.

8. In combination, afloor slab, a surface covering thereon, a duct Within the floor slab, a fitting applied to the duct to give access to the duct through the floor, the fitting extending tothe edges of the fioor covering whereby patching of the floor covering is avoided.

9. A concrete floor construction comprising in combination, a course of suitable material constituting a floor slab, a course of suitable material disposed upon a level above the floor slab and constituting a floor surface, a course of suitable filling material disposed intermediate the floor slab. and floor surface, and an arched wiring conduit of greater width than height disposed entirely within the intermediate course, for Wiring, to which connections are to be subsequently established through the Hoor surface.

10. A concrete floor construction com rising in combination, a floor slab an an upper floor surface layer, an arched conduit disposed entirely between the floor slab and the fioor surface` layer, extending to within a prescribed distance of all parts of the fioor urea, and an outlet fitting anchored in the floor surface and extending downward into said arched conduit.

11. A concrete fioor construction comprising a floor slab and an upper floor surface, an larched conduit of greater Width than height, having a substantially flat bottom and disposed entirely between the floor slab and the floor surface, reaching within a prescribed distance all parts of the floor area, said conduit being suitable for subsequent lentry at any portion of its length to receive an outlet fitting and for installment of Wiring therein when required.

12. 4A concrete floor construction comprising a fioor slab, an upper layer of Hoor surface material, and an arched conduit of fibrous material or-the like f greater Width than height, disposed entirely beneath the Hoor surface, within a prescribed ,distance of all parts of the floor area to be served, and adapted to be penetrated at any point after completion of the Hoor to receive'an outlet fitting.

13. Aiconcrete floor construction `comprising a floor slab, an upper continuous floor surface layer, an intermediate layer of filling material between them, and an arched conduit embedded in said filling material,-

adapted to Abe penetrated at desired points after the completion ofthe floor for" installing wiring as required.

14'.A wiring arrangement for floor construction comprising two sets of branched conduits, for two independent` systems of wiring, the branches of one set intercalating with the branches ofthe other set so that every point of thefloor space to be served will be within a prescribed minimum distance from a conduit of either set, without .requiring crossings of the two sets.

15. A concrete floor construction comprising a floor slab, an arched conduit o en at the bottom, laidon said floor slab, a 'll laid over and covering said conduit, and a layer of floor surface material laid over said fill.

16. A concrete floor construction comprising .a floor slab, open-bottomed arched conduits laid oli-said fioor slab, a filling between and overfthe conduits and a surface floor laid over and covering said filling. 17. A wiring arrangement for floor construction comprising two independent systems of continuous runs of conduit spaced ing s1ab,;laying an arched wiring conduit in the'space above the supporting slab, covering said arched conduit with a fill laid upon said supporting slab, and laying a superficial course o-f suitable material over said` fillto constitute a floor surface.

19. The method of -laying and utilizin conduit in the construction of fioors lwhic comprises placing the conduit on a lower course of the floor, cementingthe edges of the conduit to securethe same, then applying a fill over the conduit and cement, then covering the whole with an integral surface floor and subsequently cutting through the surface fioor and into the conduit and 'applying an outlet fitting.

20. .The method of laying and utilizing conduit in fioors which comprises placing tlie conduit on a lower course of the floor, then applying filling material around and over the conduit, then covering the whole with a continuous integral surface floor, and subsequently cutting through the surface floor' and into the conduit and applying an outlet fitting, and introducing the wiring.

21. A concrete floor construction comprising a floor slab, a concrete'floor surface a wiring passage disposed entirely beneath -`the surface of the concrete'fioor and formed by a non-metallic fibrous conduit of half round section open atthe bottom, the bottom of said passage being closed b the floor slab on which the conduit is lai 22.' A wiring duct arrangement for floor construction 'comprising `two independent runs of .conduit spaced apart beneath the floor surface substantially in one plane, 'a'nd each having a lateral branch extending toward the other.

23. A wiringY arrangement for floor construction comprising two independent systems of continuous runs of conduit'. spaced apart at intervals beneath the floor' 4sui-.face in one plane, those of one system 'alternating with those of the other,and eachrun having a yplurality of lateral branches extending substantially across the space'intervening between the runs ofthe two' Systems.

24. A wiring arrangement for building construction comprising two inde endent systems ofV wiring. conduits disposed eneath the surface of a buildingfloorin substantially the same glane, each system having main ducts exten ing across the area ofthe floor and yspaced lateral ducts extending at right angles from the main ducts, the main ducts of one system being parallel to the main ducts of the other system and the lateral ducts of one system being parallel to and intercalating the lateral ducts of the other system.l l

HENRY F. RICHARDSON. ALLAN COGGESHALL. 

